Thermal control device



Nov. 28, 1944. F. R. HIGLEY'ETAL THERMAL CONTROL DEVICE Filed Dec. 24, 1941 N W m Patented Nov. 28, 1944 THERMAL CONTROL DEVICE Frank R. Higley, Cleveland Heights, and Julius Converse, East Cleveland. Ohio, assignors to The Bryant Heater Com a corporation of Ohio Application December '24, 1941, Serial No. 424,284

Claims.

This invention relates to improvements in thermal control devices, that is to say, devices of the compensated type, and more especially devices a of this character which may be utilized in a novel manner for safety pilots.

An object of the invention is the provision of a compensatedthermal control device of great simplicity and low cost, but one which, nevertheless, is more sensitive thermally than other devices now in wide commercial use.

Anotherobject of the invention is the provision of a thermal control device which itself shall function as a pilot tube.

A further object is the provision of a thermally responsive device in the form of a. pilot tube with a tongue mounted inside the tube for communicating motion therefrom to a suitable control.

Another object is the provision of a tongue of special form having special advantages.

Still another object is the provision of means for providing a Bunsen burner effect in a combined pilot tube and thermal control device, and, further, for utilizing one of the air intake ports in such a burner as an opening through which motion may be communicated from the internal tongue to external control apparatus.

Other objects and features of novelty will appear as we proceed with the description of that embodiment of the invention which, for the purposes of the present application, we have illustrated in the accompanying drawing in which:

Fig. l is -a plan view partly in horizontalsection of a device embodying the invention.

Fig. 2 is a side elevational view of the same:

Fig. 3 is an eievational view of a slightly modifled form of the invention looking in the direction opposite that of Fig. 2;

Fig. 4 is an end view looking in the direction of the arrows 4-4 of Fig. 1;

Fig. 5 is a view of the opposite end of the device;

Fig. 6 is a fragmental 'elevational view looking in the direction indicated by arrows 6-.6 of Fig. 5;

Fig. 7 is a fragmental central sectional view of a portion of the device'on a larger scale;

Fig. 8 is a detail cross-sectional view taken substantially on the line 8-801. Fig. 7; and

' increase its flexibility at that the lower half of the tube Fig. 9 is a detailsectlonal view on the same scale as Fig. 8, the view being taken substantially on the line 8-! oi Fig. l. i

The thermally re ponsive element of the invention consists primarily of an elongated tube III of material responsive to heat-and not subject to rapid deterioration because of heat, preferably a steel alloy. While a tube of uniformly thin wall 1 shownclosed at this end gether so that the flame of them, it being understood that these flames pany, Cleveland, Ohio,

throughout may be used, we prefer to employ one of fairly heavy gauge and to' machine a series of grooves II in a short length or the tube to point andfor other reasons, as will presently appear. The tube is caused to flex for effecting the operation of suitable control apparatus, as, for example, a gas valve, and this fiexure is brought about by the application of heat to one side only of the tube, whereby that side expands throughout the heated pogtion and causes more or less bowing of the tu e. effective insulation against the transfer of heat in a straight course from the hot side of the tube to the cold side. and while some leakage takes place through thewallof the tube, the section through which it passes is relatively thin and cuts down the flow of heat to such an extent that it 7 becomes of relatively little importance.

While heat may be applied by the application of a flame from a burner outside the tube we prefer to utilize the tube itself as the gas conthe tube. This arrangement of the ports in the ribs I3 is advantageous from the standpoint of entraining secondary air, while the ribs themselves provideadditional metal for the absorption of heat. In a horizontally arranged tube, as herein illustrated, the ports l2 are located in somewhat to oneside of the vertical median plane so that flame result ing from gas issuing from these ports will wipe one side of the tube and not tend to flow under the tube to the other sidethereof. I4 is an igniting port that is adaptedto light a burner -(not shown) with'which the tube I 0 may be associated as a pilot tube. After the gas from port I4 is'ignited, that from the nearest port i2 will flow upward and be ignited from the first flame and the remaining ports l2 are arranged close enough toare quite small as compared to that of the igniting port I4. When the tube is arranged vertically or otherwise than horizontal, it will be convenient oftentimes to have the igniter port in the end of the tube, but in the present instance the tubeis by a plug I5.

In the illustrated embodiment, the tube is supported near its opposite end by being extended through a round. opening of suitable size in the intermediate wall 18 01' a three-sided sheet metal frame. Between the other walls I! and I8 of this The air within the tube, of course, forms quickly spreads to all 1 tachment and the area of flexure.

- through this port.

.frame there is mounted a block l9 having a bore therethrough threaded at for connection with gas tubing. The opposite end of .the block is turned down to cylindrical form of a size to fit in various ways to effect the operation of control apparatus. One means which we have discovered for doing so is to mount a tongue within the tube attached to the tube and adapted to communicate movement back away from the point ofat- The tongue which we prefer to employ is a tongue 23 of U- shaped cross-section, the curved back of which is attached to the tube III by brazing or welding, as indicated at 24. The free end of the tongue 23 terminates in the vicinity of the air ports 22.

In order to interpose no interference with the entrance of air, the curved back of the tongue may be cutaway at this point, as indicated at 25.

Means for transmitting the movement of the free end of the tongue in response to flexure of the tube may extend through one of the ports 22, and this'is done in the illustrated case by having a spring finger 26 of a microswitch 21 project The details of the microswitch-are of no importance in this case, it being essential merely that a. very small movement shall sufllce to open or close the switch. As shown herein, the switch includes a plunger 28 which, when moved inwardly, makes a contact. It comprises two binding posts 29 and 30 for connection with conductors of an electric circuit. When the tube-is heated by flames from ports l2, the resulting flexure of the tube causes the free end of tongue 23 to press finger 26 and thereby push on plunger 28 for closing the electric circuit. The latter may be arranged to operate a control such as an electrically actuated valve in a gas conductor leading to the burner with which the present pilot is associated.

The body of switch 21 is preferably fixed in the frame members l1, l8 by means of bolts 3|. Screws 32 extend loosely through holes 33 in the I frame members I1 and I8 and are threaded into the block.|9, permitting the block to be locked in different positions of adjustment within small limits. An adjusting screw 34 threaded in the block I9 bears against the body of switch- 21.

' When the screws 32 have been loosened, screw 34-may be turned one way or the other to separate block l9 and switch 21 more or less, whereby the tube I0 is tilted one way or the other in its bearing in frame member l6, which effects adjustment of the tongue 23 with respect to the finger 26, thereby regulating the speed of operation a of the device after heat is applied to the tube. The-adjustment may be secured by other means, however.

In Fig. 3 we have shown a pilot tube 33 of ment being more or less distant from the extreme by small intervening ports 31, the purpose of which is solely to carry igniting flame from port 36 to ports l2. These ports 31 are in the top of the tube in line with port 36, and therefore have no heating effect.

To those skilled in the art. the-operation of the device, it is believed, will be apparent from the foregoingdescription. While we have necessarily gone somewhat into detail in order to explain fully the particularembodiment of the invention herein illustrated, we desire it to beunderstood that such detailed disclosures are-not to be construed as amounting to limitations except as they may be included in the appended claims.

Having thus described our invention, we claim:

1. In a device of the character described. a pilot tube constituting a laterally flexing thermal element of the compensated type, said tube being fixed at its inlet end only and being closed at its free end, and havingan exit port in its side wall the flame from which is adapted to heat the tube on one side and cause flexure thereof,

tached at one end thereto remote from 'the supported end of the tube, said tube having an air intake opening therethrough near its supported end, and control apparatus operatively connected with said tongue through said opening.

3. In apparatus of the class described,-a thermal control device of the compensated type comprising a tube, said tubehaving in a portion of its length a series of peripheral grooves for in-'' creasing flexibility, means for heating the grooved portion of the tube along one side of the latter to cause flexure, and means for utii iizing said flexure to operate a control.

4. In a device of the character described, a pilot tube, said tube having in a portion of its length a series of peripheral grooves for increasing flexibility and having gasexit ports in said grooved portion between the grooves thereof arranged in longitudinal alignment for heating the tube on one side and causing flexure thereof,

p and means for utilizing said flexure to operate latter and extending therefrom toward the suD- greater length than that in the other figures of the drawing, that is to say, one which extends considerably beyond the points of attachment 24 of the tongue 23 to the tube, these points of attacha control.

5. In a device of the character described, a pilot tube supported at one end, a tongue attached to the tube near the opposite end of the ported end, said tube having a gas exit port intermediate the ends of the tongue the flame from which port is adapted to heat the tube to cause flexure thereof, and control apparatus arranged .to take movement from the free end of the tongue. a

6. In apparatus of the character described, a thermally responsive device comprising a tube, means for heating the tube on one side to cause flexure thereof. mounting means disposed endwise of the tube one way from the point of application of heat, and a tongue within the tube secured at one end to the side thereof opposite the heated side at a point disposed the other way from said point of heat, application; said tube having an openingthrough which the effects of the movements of said tongue maybe transmitted for the control of apparatus external to the tube.

'I. In apparatus ot the character described, a

thermally responsive device, comprising a tube mounted at one end, means for heating said tube on one side to cause flexure thereof, and a tongue within the tube of channel-shaped cross-section with its back attached at one end to the tube opposite the heated side of the latter, whereby radiant heat transfer is minimized, said tube having an opening through which the effects of the movements 01 said tongue may be transmitted for the control of apparatus external to the tube.

8-. In a device of the character stated, a pilot tube having a gas exit port in a side wall thereof, the flame from which is adapted to heat the tube on one side and cause flexure thereof, a,

ton ue disposed internally of the tubeand -attached atone end to the tube. said gas port being located intermediate the free and attached ends of the tongue, and means responsive to the tube with its back attached at one end to the tube opposite the heated side of the latter, said fluid may flow into and along the channel ofsaid tongue, and means responsive to the motion of said tongue,

10. In a device of the character stated, a pilot tube having an exit port in one side thereof, the flame from which is adapted to heat the tube on that side and cause flexure of the tube, a tongue of channel-shape disposed within the tube with its back attached at one end to the tube opposite the heated side of the latter, said port being located intermediate the free and attached ends of the tongue, means fol-mounting said tube at a point 'near the-free end of said tongue, at gas spud in the tube beyond the free end of said tongue arranged to deliver a stream 01 gas into the channel of said channelshaped tongue directed along th tube toward said exit port, said tube having a side port ar -ransed to deliver air between the side walls oi the channel-shaped tongue into the path 01 said gas stream, and means responsive to the motion 01' saidtongue.

FRANK a; mum. JULIUS CONVERSE. 

